The conventional types of automotive air conditioners have used a single type of coolant so that the contituent part of the coolant is constant at every portion in the refrigerant circuit. Therefore, the maximum cooling capacity of the air conditioner is calculated uniformly when the components of the refrigerant circuit (such as a compressor, a condenser, and an evaporator) are designed.
Since the compressor of the automotive air conditioner is driven by the automotive engine, the discharge faculty of the compressor is varied in accordance with the rotating speed of the automotive engine. Therefore, the other components, such as the condenser and the evaporator, should have a large enough capacity in order to insure the minimum cooling capacity of the automotive air conditioner even when the discharge faculty of the compressor is decreased.
The refrigerant circuit using a couple of types of
coolant having different boiling points have been employed in heat-pumps for cooling and warming residential rooms. The refrigerant circuit of a heat-pump uses a couple types of coolant in order to increase the warming capacity when the temperature of the atmosphere is low. In other words, a couple types of of the coolant do not have any advantages when such coolant is used for cooling. Furthermore, since the compressor of the residential room air conditioner rotates constantly so that the discharge amount of the coolant is constant, and constitute parts of a couple types of of the coolant of the air conditioner do not require modulation over short periods, the room air conditioner of such refrigerant circuit uses a constituent parts rectifier having a very small capacity
Therefore, the conventional
room air conditioner having a couple types of of the coolant requires more than ten hours for modulating the component parts of the coolant. The conventional type air conditioner, therefore, cannot be equipped within an automobile.